Stool



Dec. 5, 1944. J. A. CAMPBELL STOOL Filed Feb.` 8, 1943 IN VEN TOR..

ais.

Jamas (Z Patented beeft-1944 t i i `2,364,191. y 7 STooL James `A. Campbell, Adrian, `Mich., `assg'norol one-half to Charles T. CampbelLlAdrianJVIich. i `lplieaaon February s, 194s, serial No. 415,103"

The `present invention is directed 'toan extensible support providing a pair of ftelescoping members adapted for relative movement with respectto each other and having retaining `means i i `coactirig between the members to selectively lock the `same in certain* relative positions to prevent the diminution of the overall length of `the combined members. The extensible support andfits new and Anovel associated retaining mechanism is in `this case incorporated in a stool for the purpose of varying the supported `height of the seat with respect `to the floor. Y.

The stool incorporating n the `present invention is provided with two relatively movable members combined for telescopic movement, with one of I the memberslsecured'to vthe `seat of tliestooland the other member secured to Athe legs pr base of the stool and with the new and 'novel form of retaining means coacting between `the relatively movable members for the purpose of adjusting the'seat height. The foregoing retaining `means functions to lock the two movable members" in `various selected 'positions and may be released fromlocking "position forthe purpose of readjusting 4the chair from a higher seat level to a i lower seat level.`

The new and novel features of the invention will be more` specifically explained and pointed out in the following detailed description thereof having reference to the accompanying drawing.

disclosing a preferredjform of stool;

ln the drawing:

Fig. 1 is a side `elevationalviewof the stool incorporating the present invention.

Fig. 2 is a vertical' longitudinal sectional view` along the chair columnas takensubstantially` along theline 2`2 in Fig; l, illustrating `most of 1 the interior mechanisms elevation. i

` Fig. 3 isa cross-sectional View taken vertically along thecolumn` of the `stool substantially` as in Fig.` 2, but further showing the retaining4 means andqits associated mechanism in cross-section.`

Fig. l is another cross-sectional View of the f upper end portion of'FigB illustrating the manner in which the rolling elementsof the retainy ing means` are disposed in aposition for locking the relatively movable members ofthe chair col# umn after `said members are moveda predetermined amount; ands` t i y Fig. 5 is another vertical sectional View through the column illustrating the release ofthe rolling elements from locking position for the purposes of re-setting the seat height of the stool. Q Fig; 11 illustrates a stool havinga seat -l` sup-` ported by an` extensible "column l2 having :the

lol. 155-94) i tubular 4member 3 :secured tothe legi4 base il; fReferring `to Fig. -3, the `stool seat-l is rotatably carried upon a suitable bearing `5 A which rests upon the reduced endof the columnmember VL6 5 and these parts are held together by meansof a suitable `fastening lnut lorfin any 'other manner desirable. The column members 23. andf com` prise the 1tworelatively movable members of the extensible column "and these :members are ar- 10 ranged in `telescopic relationship in the manner illustrated; i i i The retaining means cooperating `between -the two` relatively `movable members 3 and 6 com# prises a housing `8 in theform of the `sleeve that is suitably-secured to the end ofthe tubular member 3`jin anysuitable manner. t In thepresent construction thesleeve -orhousing 48 `is provided with an annular groove Bfbordered byothe serrations Ill and Il, and the walls of the tube 3 are spuninto the annularvgroove as at12 to rigidly secure saidimembers together. The` groove 9 prevents endwise. separation of :the members 3' and vll, .while the serrations lll and Il `will :prevent relative rotary movement of the same mem i bers. *The housing is provided `with a conical )chamber l3 terminating in a n"shoulder I4 for supporting Athedisc I5` to provide closuretmeans forfthe upperfend ofthe housing A8; -By-spinning n `or crimping :overthe extreme end I6 `of the housings `nponthe upper race of the `discwli, the

latter is xedly secured to :the housing.

' JA plurality of rolling `elements inthe form of ball bearings l1 areiloosely `carried within `the i conical chamber lf3 `.of `the housing 8 and `are adapted for enacting between the 4walls ofthe `chamber `I3 and `the surface Lof thewcenter sup- `D0rt or movable column membervl It should be noted :thatthe chamber `I3 of thehousing i8 may lbe otherwise formed" and `.does not` necessarily 4o needtolbehcomcally or circular las shown, and n that the rollingelementsA need not be ball. bearingsand may be replaced `byrollers for the like. v

-wOpposte'ly disposed with respecttothe rolling 1 elementsiorlballs Il are a pairiof sleeves -IB and 1B' which constitute shiftablemeans for extending 'outwardly at both ends `from withindthe house ing i8 and which sleeves cooperate withvtherolb ing elements within tbehousing. The sleeve i8 is looselycarried between the disc l5 oi the housing and the outer surfaceof the `member `t and normally restsupon the balls `I-'lby gravity. The sleeve`l8, therefore, normally tends to urge or hold the `balls `I'l `in lockingposition'betweenithe `walls of'ithe chamber; I3 `and themember, and lili a suitable annular flange 20 -isV `provided :at the lower end of the sleeve IB for the purposeof preventing withdrawal of said sleeve from the ho-using 3. The annular iiange 2li further p-roy vides means for normally contacting the balls I'l in all positions that the latter may assume during the operation of the adjustable column.

The other sleeve I9 is split as at 2| and is formed to be inherently springy for the purpose of self-expansion within the bore 22 of the housing 8 and is, therefore, held in frictional engagement to be held directly within the bore 22 of the housing 8 at all times. The central column member 6 is suitably guided by the mechanism of the retaining means a1; one point while the, extreme lower end o-f the column is provided with a suitable fitting 23 formed with a plurality or"` projections such as 24 which are adapted to en` l gage the interior wall of the xedcolumn 3 for the purpose of vertically guiding and stabilizing the member 6. The projections 2li have been provided for the purpose of reducing frictional contact. The tting 23 is also providedwith an elongated sleeve such as 25 which is of such a length as to form labutment means connected with the column 6 for the purpose of engaging the shiftable means of the retaining means as will hereinafter be described. 4Tl'ie iitting 23 is secured to the end of the column 6 by means of the nut 2t threaded ruponthe reduced end 21 of f the column, relative movement of saidmembers being prevented by means of the shoulder 28. Obviously, suitable shims or washers could be inserted about the shank 27 and between the column 6 andthe shoulder 28 for the purpose of raising o-r lowering the end 29 of the fitting 23 with respect to the end of the column 6 to procure the proper functioning or the retaining means.`

The entire retaining mechanismand the associated parts are enclosed by a suitable tubular guard 30 which is connected with the boss of the v stool seat I in any. desirable manner and it will benoted that the guard 30 and column move together simultaneously with the movement of the stool seat I. A suitable friction ring 3| is carried by the lower end of the guard 3l) for the purpose of preventing dust and dirt from entering into the operating mechanisms of the adjustable column. This ring 3| is preferably made of leather and provides a friction member for coacting Ibetween the `guard 30 and the tubular column 3 to frictionally retard movement of the guard 30 and column 6 relative to the tubular and stabilizing the stool relative to the xed base f members thereof by reacting against bending or tilting of the inner structures of `the column. Also, the guard 3l) enhances the appearance of the chair. lTo render the retaining means operative fo supporting -the stool seat at various heights, the parts of the stool are positioned as illustrated in Fig. 4 by pressing downwardly upon the stool seat I when the latter is in lowermost position. This causes the abutment means secured to the column 5, which in this case may be the roller bearing 5 or the internal shoulder 35 of the boss of the seat,

to move the loose sleeve I8 downwardly into the housing 8 through the instrumentality of a washer 3S. The washer 36 has been provided as a means for preventing the relatively thin sleeve I8 from entering the bearing 5 or other means that may be provided at this point, such washer also being of a size to contact the upper ends of the spun-in portion I6 of the sleeve 8. In this manner, the sleeve I8 is moved inwardly a dennite amount every time that the chair parts are in the position shown in Fig. 4. The movement of the sleeve I8 presses the balls I'I downwardly within the conical chamber I3 of the housing 8, the balls I'I at the same time engaging the frictional sleeve I9 moving the latter outwardly of the housing in the manner illustrated in Fig. 4.

In order that the foregoing operation may be properly performed and to prevent jamming of the parts such as might occur when the balls I'I are forced between the walls of the conical chamber I3 and the surface of the column 6, the latter is provided with an annular recess 37 which establishes suitable clearance for the balls I1 and provides means for rendering such balls inactive while disposed in operative position until the relatively movable members 3 and 6 have been moved a predetermined amount and in the present instance that would be the Width of the annular recess 3l. When such movement takes place, the balls I'I are slightly raised and moved outwardly by means of the beveled edge 38 of the recess 3l which will then place the balls VI'i into their normal active locking position between the walls of the chamber I3 and the surface of the column E and free of the sleeve I9. Thereafter the raising of the seat I will move the guard 30 and the column 5 upwardly relative to the tubular nxed member 3, drawing the column 6 through the retaining meanswhereby the balls I'I will lock the column E in any position within the limits of movement or expansibility of the chair column for supporting the seat at any selected elevation.

For resetting the seat of the stool in order to obtain a lower seat elevation, the seat I is raised to its extreme position which will place the operating mechanisms ofthe stool in the position indicated in Fig. 5. Here the end ZSof the fitting 23 has engaged the sleeve I9 moving the latter inwardly of the housing B raising the balls Il into the position shown where they are in inactive or inoperative position inasmuch as they are moved out of wedging engagement from between the walls of the chamber I3 and the surface of the column 6. This action also raises the sleeve I8 and washer 35 into the positions illustrated and Vsince the sleeve i3 is frictionally maintained within the housing R, the center column 6 including the iitting 23, stool seat I and guard 30 may then all be moved downwardly with respect to the tubular column 3 until such parts are again placed into the position' illustrated in Fig. 4 whereupon the seat height may again be adjusted as desired.

It is obvious that the present eXtensible column will permit of various applications and need not be limited to a stool such as shown and described. Such a column may be utilized for table legs, furniture legs or multiple chair legs or various other uses where it is desirable to incorporate, an extensible support such as described. It is also contemplated to make various modiiications in the detailed construction of the present device and the same is, therefore', not to be limited to the exact form, construction, arrangement or assen ai` combination of` parts as specifically referred to and described or tofthe `particular uses hereinI mentioned. All modifications and changes shall `be governed by the breadth and scope `of `the appended claims. i

What I claim as new and "desi-re to secu-roby Letters Patent "is:

1. In an adjustable stool or the like,the combination `of two relatively movable telescoped members coactingto support the stool seat, retaining means connected between said `members Y to lock the same against `relative movement in lone direction andto allow said members to be relativelymoved inthe opposite direction to adjust the supported height of the seat, said retainagainst relative "movement infone direction :and

to allow said members to be relatively moved fin thefyopposite direction to adjust the `supported height of the seat, said retaining means Lcom- `prising a housing connected `with one of `said members and encircling the other member, `said i `housing h'avingga conical chamberrtherein, rolling ing `means 'comprising a housing'connected with circled member, shiftable sleeve means extending `outw'ardlyfrom the ends of said housing `and cooperating with said rolling elements within said housing to dispose the elements in operative locking position or to move the same into inoperative position, respectively, whereby said members may be lockedin said one directionor `released therefrom, andjupper and lower abutment members rigidly connected to said encircled jmember for shifting said shiftable sleeve means whenthe encircled member approaches the limits of its movements in "either direction, said encircled member having an annular recess located adjacent the upper 'abutment member forjrelieving the'rollingelements of frictional engagement `with the `wall `of the conicalchamber and encircled member.`

elements in said ychamber adapted-for locking en-` gagement between the walls of said 1 chamber and the `surface of the encircled member, shiftable `mear-is extendingoutw-ardly from the ends of said housing and cooperating with `said rolling `elements within saidhousing todispose the 'elements in operative 'locking Vposition or to move the same into inoperative position, respectively, whereby said relatively movable members `may be locked in said one direction `or released therefrom, upper and lower abutment members connected with the encircledone of said `movable members to engag theshiftable meanstocause the rolling elements i to be disposed in operative or ininoperative posi# tions, respectively,` rand `said encircled member having an annular recess adjacent the upper one of said abutmentimembers'for rendering said rolling elements inoperativewhen shifted `into -operative locking positionV by said upperlabutment member and shiftable means,` until said two relaL tively movable members are ymoved relative `to i eachother a predetermined amount.`

`2. In `an `adjustable stool orthe like, the 'comh bination fof two relatively movable `telescoped members 'coacting to support a stool seat, retaining means connected between said members to lock the same against relative movement in one direction and to allow said members `to berelatively moved in the `opposite direction to adjust the supported height `of `the seat, said `retaining means comprising ahousing connected with one of said members and 'encircling the `other member, said housing having 4a conical chamber therein, rolling `nements in said cnamberadapted for locking `'engagement between the `walls of jsaid chamber and the' surfaceof fthe encircled member, shiftable `sleeve means one extending upwardly from saidhousing, and one downwardly, the Vdownwardly projecting sleeve means -being and said sleeve means cooperating with `said rolling elements within said housing to dispose the rolling elements in operative locking 'position or Vto `move `the same into `inoperative position,` respectively, `whereby said members may be locked insaid one direction or released therefrom; `and upper and lowerfabutment Ameans rigidly Acon,- nected to the encircled `one of saidmovablemem- `bers at'the 'ends thereof for engagementV with the` projecting portions of the shiftable sleeve means 3. In `an adjustable stool or the likeQthecombi-` nation `of two relatively movable members coacting to "support the `stool seat, retaining means M :connected between said members `to lockthesame frictionally engaged with the wall of the housing,`

4. In an extensible support, the combination of 'a pair 4of telescoping membersadapted for relative movement, retaining mechanism coacting between said `members to fselectivelyllockthe same in `certain relative positions to prevent the diminution of `the -overall length oi" saidfcom'bined members, said retaining mechanism coinprisingfA a housing connected with one of said members and encircling the other memberpsaid housing having a conical `chamber therein, rolling elements insaid chamber adapted for locking eni gagement between the walls offthe `chamber and "the surface of the encircled member, shiftable sleeve `means projectingifrom the ends of said housing and cooperating withfsaid rolling elements within the housing to position the elements approaches the limits `of itsmovements in `either direction, and said encircled member having an h annular Arecess located adjacentsaid upper abutmentmember, whereby therolling elementsare `frictioi'ia'lly disengaged fromthewallof the conif` cal Chamberland `encircled telescopingmember l h when the latteris lowered to the "lower limit of its movements. i

5. *Inan entensiblesupport, the lcombination of i a :pair of telescoping members adaptedfor relative movement, retaining mechanism coacting bel 'tweensaid members to selectively lock the same in certainrelative positions to prevent the dimiinution ofthe overallilength of "said combined members, "said retaining mechanism `comprising a housing connected with one `of said members and encircling the other membensaid housing f having 'a conical `chamber therein, rolling elements vin said 'chamber adapted for locking enmeans projecting from the ends of saidv housing and cooperating with said rolling elements within the housing to position the elements in operative locking position or to move the same into inoperative position, respectively, whereby the overall length of the combined members may be adjustably increased or whereby the overall length of the combined members may be diminished for purposes of readjustment, and upper and lower abutment means rigidly connected to one of said telescoping members for engagement with the projecting portions of the shiftable means to cause the rolling elements to be disposed in operative or in inoperative positions, respectively, said lower abutment means comprising a sleeve surrounding the encircled member and extending upward from its lower end.

6. In an extensible support, the combination of 'a pair of telescoping members adapted for relative movement, retaining mechanism coacting between said members to selectively lock the same in certain relative positions to prevent the diminution of the overall length of said combined members, said retaining mechanism comprising a housing connected with one of said members, and encircling the other member, said housing having a conical chamber therein, rolling elements in said chamber adapted for locking engagement between the walls of the chamber and the surface of the encircled member, and shiftable means projecting from the ends of said housing and cooperating with said rolling elements within the housing to position the elements in operative locking position or to move the same into inoperative position, respectively, whereby the overall length of the combined members may be adjustably increased or whereby the overall length of the combined members may be diminished for purposes of readjustment, upper and lower abutment members connected with the encircled one of said telescoping members to engage the shiftable means to cause the rolling elements to be disposed in operative or in inoperative positions respectively, and said encircled member having an annular recess adjacent the upper one e .tween said members to selectively lock the same in certain relative positions to prevent the diminution of the overall length of said combined members, said retaining mechanism comprising a housing connected with one of said members, and encircling the other member, rsaid housing having a conical chamber therein, rolling elements in said chamber adapted for locking engagement between the walls of the chamber andl the surface of the encircled member, andshiftable means projecting from the ends of said housing and cooperating with said rolling elements within the housing to position the elements in operative locking position or to move the same into inoperative position,- respectively, whereby the overall length of the combined members may be adjustably increased or whereby the overall length of the combined members may be diminished for purposes of readjustment, upper and lower abutment members connected with the encircled one of said telescopingy members to engage the shiftable means vto cause the rolling elements to be disposed in operative or in inoperative positions respectively, and the encircled one of said telescopic members having an' annular recess therein adjacent the upper abutment member adapted for cooperating with said shiftable means to render said rolling elements inactive when shifted into operative locking position `by said upper abutment` member and 'shiftable means, until said two telescoping kmembers are moved relative to each other a predetermined amount, said annular recess having a tapered edge portion for operatively shifting said rolling elements into active locking engagement between the chamber wall and the surface of the encircled member upon completion of said predetermined relative movement of said telescoping members.

S. In an extensible support, the combination of a pair of telescoping members adapted for relative movement, retaining mechanism coacting between said members to selectively lock the same in certain relative positions to prevent the diminution of the overall length of said combined members, said retaining mechanism comprising a housing connected with one of said telescoping members and encircling the other member, said housing having a conical chamber therein, rolling elements in said chamber adapted for locking Aengagement between the walls of the chamber and the surface of the encircled member, and shiftable means projecting from the ends of said housing and cooperating with said rolling elements within the housing4 to position the rolling elements in operative locking position or to move the same into inoperative position, respectively,

whereby the overall length of the combined members may be adjustably increased'or whereby the overall length of the combined members may be diminished for purposes of v readjustment, said shiftable means comprising a pair of sleeve members oppositely disposed with respect to the rolling elements within the housing, one of said sleeve members being frictionally engaged with the wall of said housing and the other of the sleeve members being loosely carried by the housing, upper and lower abutment members mounted on the encircled member, and said nencircled member having an annular recess therein adjacent the upper abutment member to 'prevent jamming of the rolling elements when shifted into operative position, said recess having a tapered edge portion yadapted to move the rolling elements into engagement with the conical wall of the housing and surface of the encircled member, when the latter Vis moved endwise a distance equal to the width of the recess, whereby to restore the rolling elements into operative position.

9. In an extensible support, the combination of a pair of telescoping members adapted for relative movement, retaining mechanism coacting between said members to selectively lock the same in certain relative positions to normally prevent the diminution of the overall length of said combined members, said retaining mechanism comprising a housing connected with one of ysaid members and encircling the other member,`saicl housing having a conical chamber therein, roll Y ing elements in said chamber adapted for locking engagement between the walls of the chamber and the surface of the encircled member, and shiftable means projecting from the ends vof said housing and comprising a loose sleeve and a sleeve frictionallyengaging thewall of the housing, said sleeves cooperating with said rolling elements within the housing to positionA the elements in operative locking positionfor'to `move Athe "same into inoperative position, respectively, whereby the `overall"l'engtlr ofthejcombinedgmembers may be" adiusta'blyr "increased"` or `whereby the overall lengtlfr-of the combined members 'may' be dimin-v ished vfor purposes-of 'readiustmentg abutment.

members, lsaid retaining `mechanism `'comprising a housing *connected 4with `one of said members and `encircling the other member, said housing having af conical chamber therein,` rolling elements in said chamber `adapted, forloclring engagement between the walls ofthe chamber and members `connected Vwith orreof said telescoping;` members t'o engage the-ssliiftable Lmeans to-'cause the rolling "elements to be disposed* in voperative or Iin inoperativel positions *respeetivelw one of said telescopic membershavingan annular recess adapted `forrcoeperatingA withsaid shiftabl'e means to rendersaid rolling-elements inactive when shifted into operative inciting position byl said `shiftable '-means, until aid" two l telescoping members aremovedfrelative {toleac'h `other a predetermined amount, fsaid annularirecess havin an. edge portionffor r"operatively shifting said *rolling' elements in'to factivefloclirig l engagement between 'the chamberwallf'and-the surface of the encircled l member lupon i completion ,ofjsaid predetermined relative *movementof said telesceping the surface rof the encircled member, and shiftable means'proj'ectingfromtheends of said housing land,coo,perating` with said rollingv elements `vvithinrthe housing :to position 'the rolling ele,`

merits-fin loperative locking: position, or to 'move the Ysame `into @inoperative position, respectively, whereby` theyoverall length ,of :the lcombined mem- ,bersJ maybefadjustably increased orwhereby the.

members,` and va -i?langec`onnected withV said loose sleeve-for preventingisparation o'f fthe latter from the housing; `said lian-gel` beingfadapted -for lbearf ing upon said `rolling elements 'to 'normally `urge the latter toward flocking Aposition by the Weight l of "thevsleeve, .saidflan-ge being adapted -to lmaintain thisrrelationsh-ip-forfall movements of said l rolling elements.

10. In an extensible support, the combination of a pair of telescoping members adapted for relative movement, retaining mechanism coacting between said members to selectively lock the same in certain relative positionsto prevent the diminution of the overall length of said combined members, said retaining mechanism comprising a housing connected with one of said members and encircling the other member, said `housing `having a conical chamber therein, rolling elements in said chamber adapted for` locking engagement between the wallsof the chamber and i the surface of the encircled member, and shiftable means projecting from the ends of said housing and cooperating `with said rolling elements within the housing to position the elements in operative locking position or to move the same into inoperative position, respectively, whereby the overall length of the combined members may be adjustably increased or whereby the overall length of the combined members may be diminoverall length" of the `combined members maybe diminishedf` flor purposes orf readjustment, said shiftable lmeanscomprisingfa pair of sleeve members oppo'sitely-fdisposed"with respect to the rollingelementswithin the Ehousing; -oneoi said sleeve members 'being lfrictionally carried'by said `housing and thefotiherllofithe `sleeve members being o looselyrcarried `by *the housing",` `and one of said tele'scop'ng members having ari annular `recess n therein cooperating `with one of said lsleevesfto f position the rolling-elements in inactive operativeV f position funtilsaid tvvo telescoping members `are movedrelativeto each-,other a predetermined o amount, said :annular lrecess `having- `an edge tporftiony Afor operatively sliiftingsaid rol-ling elements i into active locking engagement between the chamber wall and the surface of the encircled memberupon completion of` said predetermined relative movement ofsaid 4telescoping members,

and abutments rigidly connected to lone of said movable members `for shifting said shiftable means when the relatively movable members ap- ,i proach the `limits `of their movements in either ished for purposes of readjustment, said shiftable means comprising a pair of sleeve members oppositely` disposed with respect to the rolling elements within the housing, one of said sleeve members being frictionally carried by said housing and the other of the sleeve members being loosely carried by the housing, and one of said telescoping members having an annular recess therein cooperating with one of said sleeves to position the rolling elements'in inactive operative position until said two telescoping members are moved relative to each other a predetermined amount to l cause active engagement of said rolling elements,

and abutments rigidly connected to` one of said movable members for shifting said shiftable means when the relatively movable membersapdirection. v

12. In an extensible support,the combination of a pair of telescoping members adapted for relative movement, retaining mechanism coacting between said members to selectively lock the same o w incertain relative positions to prevent the diminution `of `the overall length of said combined members, said retaining mechanism comprising a housing connected with one of said members and encircling the other member, said housing having a conical chamber therein, rolling elements in said chamber adapted for locking engagement between the Walls of the chamber and `the surface of the encircled member, shiftable means projecting from the ends of said housing and cooperating withsaid rollingelements within the housing to position the rolling elements in operative locking, positi-on or to move the same into inoperative position, respectively, whereby the overall length of the combined members may be adjustably increased or whereby the overall length of the combined members may be diminished for purposes of readjustment, upper and lower abutment members rigidly secured to the encircled member for shifting said shiftable means when the relatively movable members approach the limits of their movement in `either direction, a tubular guard connected to and movable with said encircled memberand enclosing the telescoping members and `frictional means proach the limits of their movement in either dil connected with one of said telescoping members and engageable with the tubular guard to retard` free relative movement ofsaid tclescoping mem-` bers whenever the rolling elements are disposed o in inoperative position.

13. In an adjustable stool or the" like, the combination of twotelescoping members, one mov- `able in `a longitudinal direction relative to the other and coacting to support` the stool seat, retaining meansconnected between said members to lock the same againstl relative movement in one direction and to allow said members to be relatively moved in the opposite direction to adjust the supported height of the seat, said retaining means comprising a housing connected with one of said members and encircling the other member, said housing having a conical chamber therein, rolling elements in said chamber adapted for locking engagement between the walls of said chamber and the surface of the encircled member, shiftable means extending outwardly from the ends of said housing and cooperating with said rolling elements within said housing to dispose the rolling elements in operative locking position or to move the same into inoperative position, respectively, whereby said members may be locked in said one direction or released therefrom, upper and lower abutment members rigidly secured to the encircled member for shifting said shiftable means when the relatively movable members approach the limits of their movement" in either direction, and a tubular guard member connected with one of said relatively movable members to enclose and shield said retaining means, said guard having frictional means coacting with the outer of said relatively movable members to retard free relative movement of said telescoping members whenever the rolling elements are disposed in inoperative position.

14. In an adjustable stool or the like, the combination of a vertically movable seat supporting post, a stationary tubular member telescoped over said post, a housing connected to saidy tubular member and encircling said post, said housing i having a conical chamber therein, rollingA elements in said chamber adapted for locking engagement between the conical wall of the housing and the surface of the post, shiftable sleeve means in said housing andv comprising one sleeve extending upwardly from the upper end of the housing and a second sleeve extending downwardly from the lower end of the housing and frictionally held therein, said shiftable sleeve means cooperating with said rolling elements within the housing to dispose said rolling elements in operative locking positionvor to move the same into inoperative position, respectively, whereby l said rolling members may be locked in one direc- `tion or released therefrom, said post having an annular recess adjacent its upper end to prevent jamming of the rolling members when the latter are moved into operative position, and abutments rigidly connected to said post at the ends thereof for shifting said sleeve means when the post approaches its upper and lower limits of movement.

Y, JAMES A. CAMPBELL. 

